Method of making a washer

ABSTRACT

A method of making a washer includes the steps of cutting a section of a wire material to form a blank, forging the blank in a first forging unit to form a rough blank that is larger in width and smaller in thickness than the blank, forging the rough blank in a second forging unit to form a prototype disc that is larger in width than the rough blank, and stamping and cutting the prototype disc in a third forging unit to form the washer.

BACKGROUND OF THE INVENTION

A. Field of the Invention

The invention relates to a manufacturing method, and more particularly to a method of making a washer.

B. Description of the Related Art

Referring to FIG. 1, a conventional method of making a washer 11 includes the step of directly punching a metal plate 1 having a predetermined thickness in a punching machine to form the washer 11. However, after punching, burrs form around the edges of the washer 11, so that a large amount of material is wasted. Further, the mechanical strength of the washer 11 produced from this method is poor. Moreover, even after the burrs are cut, the edges of the washer 11 are still sharp, and can cause injury to the user's fingers. This results in poor product quality.

Referring to FIG. 2, another conventional method of making a washer 23 involves using forging equipment 21 to cold forge a wire material 22 to form the washer 23. The forging equipment 21 has a feeder 211, a clamping tool 212, a hollow female mold 213, and a male mold 215 having a punch rod 214. This conventional method includes the below steps:

(a) Feeding the wire material 22 through the feeder 211. The clamping tool 212 clamps the wire material 22 that passes through the feeder 211 and sends the same to the female mold 213. A predetermined length of the wire material 22 extends out of the female mold 213, so that the wire material 22 is divided into a clamped section 221 located within the feeder 211, and an exposed section 222 extending out of the female mold 213.

(b) Actuating the male mold 215 to move toward the female mold 213, and forging the exposed section 222 to form into a prototype disc 223 having a desired thickness and shape.

(c) Actuating the punch rod 214 to punch a through hole into a central portion of the prototype disc 223 to thereby form the washer 23. Simultaneously, the punch rod 214 pushes down the clamped section 221 of the wire material 22 to separate the washer 23 from the clamped section 221.

(d) Actuating the male mold 215 to move away from the female mold 213 and return to the original position to permit removal of the washer 23 from the forging equipment 21.

The aforesaid steps may be repeated to repeat the forging fabrication of the washer 23.

Although the aforesaid method can forge the wire material 22 to form the washer 23 using a cold-forging method, because steps (a) and (b) involve forging the circular rod-shaped exposed section 222 of the wire material 22 only once to form the circular flat-shaped prototype disc 223, the rate of deformation of the material is high, which will lead to poor mechanical properties of the washer 232. Further, since the method involves direct punching and cold forging of the wire material 22 while the exposed and clamped sections 222, 221 are interconnected and while the clamping tool 212 and the feeder 211 clamp the clamped section 221, the clamping tool 212 and the feeder 211 will absorb the applied force of the punch rod 214 and friction from the clamped section 221, resulting in gradual abrasion of and damage to the clamping tool 212 and the feeder 211. Moreover, in the forming step, the punch rod 214 must simultaneously push the clamped section 221 downward while punching a hole through the exposed section 222 to separate the washer 23 from the clamped section 221. This step requires a large forging force, which shortens the service lives of the molds 213, 215 and the clamping tool 212. Not only is the clamping accuracy affected, the rate of damage is also increased, leading to increased production costs. When the operation of the forging equipment 21 is stopped for repair and replacement, the production rate is lowered, leading to poor production rate.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a method of making a washer that has good mechanical properties.

Another object of the present invention is to provide a method of making a washer that can prolong the service life of forging equipment.

According to this invention, a method of making a washer includes the steps of cutting a section of a wire material to form a blank, forging the blank in a first forging unit to form a rough blank that is larger in width and smaller in thickness than the blank, forging the rough blank in a second forging unit to form a prototype disc that is larger in width than the rough blank, and stamping and cutting the prototype disc in a third forging unit to form the washer.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:

FIG. 1 is a fragmentary perspective view of a metal plate used in making a washer according to a conventional method;

FIG. 2 is a flow diagram, illustrating the steps involved in making a washer using another conventional method;

FIG. 3 is a flow diagram, illustrating the steps involved in making a washer using a method according to the first preferred embodiment of the present invention;

FIG. 4 is a flow diagram, illustrating the steps on how a blank gradually forms into the washer;

FIG. 5 illustrates how a first forging unit forges the blank to form a rough blank;

FIG. 6 illustrates how a second forging unit forges the rough blank to form a prototype disc;

FIG. 7 illustrates how a third forging unit forges the prototype disc to form the washer;

FIG. 8 is a flow diagram, illustrating how a blank gradually forms into a washer using a method according to the second preferred embodiment of the present invention;

FIG. 9 illustrates how a trimming device of the second preferred embodiment trims the edges of the blank;

FIG. 10 illustrates how a first forging unit of the second preferred embodiment forges the blank to form a rough blank; and

FIG. 11 is a flow diagram, illustrating how a blank gradually forms into a washer using a method according to the third preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the present invention is described in greater detail, it should be noted that the same reference numerals have been used to denote like elements throughout the specification.

Referring to FIGS. 3 to 7, a method of making a washer 5 according to the first preferred embodiment of the present invention employs a forging equipment 3 to forge a wire material 4 into a washer 5. The forging equipment 3 includes first, second, and third forging units 31, 32, 33. Each of the first and second forging units 31, 32 includes a female mold 312, 322 having a mold cavity 311, 321, and a male mold 314, 324 having a punch rod 313, 323. The third forging unit 33 includes a female mold 332 having a passage hole 331, and a male mold 334 having a punch rod 333. The method of making the washer 5 includes the steps below.

In the first step, a wire material 4 is selected according to the required material and size of a finished product, and is coiled to form a roll.

In the next step, the wire material 4 is straightened and fed to the forging equipment 3. A section of the wire material 4 is cut by using a cutting device (not shown) as it gradually enters the forging equipment 3 to form a cylindrical blank 41. As shown in FIG. 4, the thickness of the blank 41 is calculated according to the required size of the washer 5.

In the third step, with reference to FIGS. 4 and 5, the blank 41 is conveyed to the first forging unit 31 by a conveying device (not shown), and is disposed in the mold cavity 311 of the female mold 312. Afterwards, the male mold 314 is actuated to move toward the female mold 312, so that the punch rod 313 can punch and make an initial forging of the blank 41 in the mold cavity 311. The blank 41 is formed into a rough blank 42 that is larger in width and smaller in thickness than the blank 41. The rough blank 42 has a first wide portion 421, a second narrow portion 423, and an intermediate tapered portion 422 between the first wide portion 421 and the second narrow portion 423. First and second central aligning indentations 424, 425 are respectively formed in opposite surfaces of the first wide portion 421 and the second narrow portion 423. The intermediate tapered portion 422 tapers from the first wide portion 421 to the second narrow portion 423. The first and second central aligning indentations 424, 425 are provided to facilitate alignment in the next forging process. The male mold 314 is then actuated to move away from the female mold 312, and the rough blank 42 is ejected from the female mold 312.

In the fourth step, with reference to FIGS. 4 and 6, the conveying device turns the rough blank 42 upside down and conveys the same to the second forging unit 32. The rough blank 42 is placed onto the mold cavity 321 with a partial section thereof extending out of the female mold 321. The male mold 324 is then actuated to move toward the female mold 322, so that the punch rod 323 can punch and forge the rough blank 42. The rough blank 42 is formed into a prototype disc 43 that is larger in width and smaller in thickness than the rough blank 42. The prototype disc 43 has an outer annular portion 431 surrounding a central portion 433 that is thinner than the outer annular portion 431 and that has the first and second central aligning indentations 424, 425. The prototype disc 43 has two opposite surfaces both of which are indented to form the central portion 433. This facilitates the next forging process. The male mold 324 is then actuated to move away from the second female mold 322, and the prototype disc 43 is ejected from the female mold 322.

In the fifth step, with reference to FIGS. 4 and 7, finally, the conveying device conveys the prototype disc 43 to the third forging unit 33, and places the same onto the female mold 332. The central portion 433 of the prototype disc 43 is aligned with the passage hole 331. The male mold 334 is then actuated to move toward the female mold 332, so that the punch rod 333 can stamp through and cut the central portion 433 of the prototype disc 43. The central portion 433 falls down into the passage hole 331, and the prototype disc 43 is formed into the washer 5 having a through hole 51. The shape of the washer 5 in this embodiment is flat and circular. Afterwards, the male mold 334 is actuated to move away from the female mold 332, and the washer 5 is ejected from the third forging unit 33 and the forging equipment 3.

The aforesaid steps may be repeated to repeat the forging fabrication of the washer 5.

Referring to FIGS. 8 to 10, a method of making the washer 5 according to the second preferred embodiment of the present invention is shown to be similar to the first preferred embodiment. However, in this embodiment, the method further includes the step of trimming the blank 41 in a trimming device 34 before the blank 41 is forged in the first forging unit 31. The trimming device 34 includes a female mold 342 having a mold cavity 341, and a male mold 344 having a punch rod 343.

In this step, the conveying device conveys the blank 41 to the trimming device 34, and the blank 41 is placed onto the mold cavity 341 of the female mold 342. The male mold 344 is actuated to move toward the female mold 342, so that the punch rod 343 can punch and simultaneously trim the blank 41 in the mold cavity 341. Hence, the trimmed blank 41′ has a trimmed and rounded corner 411′ at one side, and a trimmed non-rounded corner 412′ at the other side. The male mold 344 is then actuated to move away from the female mold 342, and the blank 41′ is ejected from the female mold 342. In the initial forging step, the conveying device turns the blank 41′ upside down and conveys the same to the first forging unit 31 to form the rough blank 42. Afterwards, the rough blank 42 is forged to form the prototype disc 43, and the prototype disc 43 is forged to form the washer 5.

Since the step of trimming of this embodiment is performed after the blank 41 is obtained, this is advantageous in the subsequent forging forming steps to ensure neatness of an outer contour of the product. Further, since the step of trimming is added between the step of obtaining the blank 41 and the initial forging step, this may slow down the rate of deformation of the material, so that the mechanical properties of the washer 5 may be enhanced.

Referring to FIG. 11, a method of making the washer 5 according to the third preferred embodiment of the present invention is shown to be similar to the first preferred embodiment. However, in this embodiment, the structure of the female mold of the second forging unit (not shown) is altered. When the rough blank 42 is conveyed to the second forging unit and is forged to form the prototype disc 43, the prototype disc 43 is further formed with a middle protrusion 435 projecting from a middle of the central portion 433. The first and second central aligning indentations 424, 425 are respectively formed in the central portion 433 and the middle protrusion 435. When the prototype disc 43 is conveyed to the third forging unit (not shown), the third forging unit will stamp and cut the central portion 433 and the middle protrusion 435 of the prototype disc 43 so that the prototype disc 43 is forged to form the washer 5 having the through hole 51. Since the prototype disc 43 in this embodiment has the middle protrusion 435 projecting from the central portion 433, the clamping tool (not shown) can clamp stably the middle protrusion 435 to thereby facilitate conveying of the prototype disc 43.

From the aforesaid description, the method of making the washer 5 according to the present invention includes the step of initially forging the rough blank 42 between the steps of obtaining the blank 41 and the forging of the prototype disc 43, so that the blank 41 becomes the rough blank 42 first before becoming the prototype disc 43, thereby slowing the rate of deformation of the material. This enhances the quality and mechanical properties of the washer 5. Further, the uniformity of the thickness and the roundness of an outer periphery of the washer 5 are easily controlled compared to that of the conventional one-time forging method. Moreover, the independently obtained blank 41 is successively forged in the first to third forging units 31, 32, 33, or is successively forged in the trimming device 34 and the first to third forging units 31, 32, 33. Because the blank 41 undergoes the initial forging step to form the rough blank 42 and then two more forging steps, the impact force of the two forging steps are smaller than that used in the conventional single action forging method, such that the mold and the clamping tool are not as easily damaged and abraded. Hence, the service life of the forging equipment 3 can be prolonged. The object of the present invention can thus be realized.

While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements. 

1. A method of making a washer, comprising: cutting a section of a wire material to form a blank; forging the blank in a first forging unit to form a rough blank that is larger in width and smaller in thickness than the blank; forging the rough blank in a second forging unit to form a prototype disc that is larger in width than the rough blank; and stamping and cutting the prototype disc in a third forging unit to form the washer.
 2. The method of claim 1, wherein the rough blank is formed with opposite first and second central aligning indentations in the second forging unit.
 3. The method of claim 2, wherein the rough blank has a first wide portion, a second narrow portion, and an intermediate tapered portion between the first wide and second narrow portions, the first and second central aligning indentations being formed in opposite surfaces of the first wide and second narrow portions, respectively.
 4. The method of claim 3, wherein the prototype disc has an outer annular portion surrounding a central portion that is thinner than the outer annular portion and that has the first and second central aligning indentations.
 5. The method of claim 4, wherein the prototype disc has two opposite surfaces both of which are indented to form the central portion.
 6. The method of claim 4, wherein the prototype disc further has a middle protrusion projecting from a middle of the central portion.
 7. The method of claim 3, further comprising the step of turning the rough blank upside down before the rough blank is forged in the second forging unit.
 8. The method of claim 3, further comprising the step of trimming the blank in a trimming device before the blank is forged in the first forging unit so that the blank has a trimmed and rounded corner at one side and a trimmed and non-rounded corner at the other side.
 9. The method of claim 8, further comprising the step of turning the blank upside down after the blank has been trimmed and before the blank is forged in the first forging unit. 